When on a sea trial take your time. Use all the systems, check all switches to make sure they and all components are functioning. Go from bow to stearn. Don't allow yourself to be distracted and miss anything. Use all engines, get them up to operating temp, wot, idle, etc. If you have a moisture meter bring it. Look for signs of interior leaks, discolored gel on the inside around any of the holes drilled. Of course I say all this and bought one pretty much sight unseen. A few thousand into it and it's almost like new....
